package cn.com.xf.utils;

import java.util.Random;

public class CodeStr {

	//生成随机数字和字母,
	public static String getCode() {
		
		String val = "";
		Random random = new Random();
		
		//参数length，表示生成几位随机数
		for(int i = 0; i < 4; i++) {
			
			String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
			//输出字母还是数字
			if( "char".equalsIgnoreCase(charOrNum) ) {
				//输出是大写字母还是小写字母
				int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
				val += (char)(random.nextInt(26) + temp);
			} else if( "num".equalsIgnoreCase(charOrNum) ) {
				val += String.valueOf(random.nextInt(10));
			}
		}
		return val.toUpperCase();
	}
	
	public static void  main(String[] args) {
		CodeStr test = new CodeStr();
		//测试
		System.out.println(test.getCode());
	}
}